Fan and selecting method for motor size thereof

ABSTRACT

A fan includes a frame, an impeller and a motor. The impeller is accommodated in the frame. The motor connects and drives the impeller to rotate, and includes a rotor structure and a stator structure. The dimension Y of the frame and the diameter X of the stator structure meet the equation of Y=CXn′ wherein C is a constant, and n is a variable number. A selecting method for motor size of the fan is also disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

This Non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 095126094 filed in Taiwan, Republic of China on Jul. 17, 2006, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to a fan and the method for selecting the motor size thereof. In particular, the invention relates to a method for selecting matching, corresponding fan and motor sizes to achieve optimal efficiency.

2. Related Art

As electronic products increase in performance, frequency, speeds, and compactness, they inevitably encounter the problem of excessive heat production. Such heat results in elevated temperature and system instability. Therefore, heat dissipation has become one of the most important issues in designing electronic products.

Using a fan as the heat dissipating device is one common solution. As shown in FIG. 1, a conventional fan 3 includes a frame 31, an impeller 32, and a motor 33. The impeller 32 is accommodated in the frame 31, and includes a hub 321 and several blades 322 disposed around the hub 321. The motor 33 connects to the hub 321 and drives the blades 32. The motor 33 includes stator structure 331 and a rotor structure 332. The rotor structure 332 is pivotally disposed in the stator structure 331. The magnetic interaction between the rotor structure 332 and the stator structure 331 drives the hub 321 to rotate the blades 322 so that air flow can be generated.

To increase the air flux and pressure of the fan 3, a key factor is the selection of fan size and blade shape. An appropriate choice of fan size can help achieve the goals of maximal performance, minimal energy consumption, and minimal noise. During the development of fans 3, the sizes of the motor 33 and the frame 31 have often been decided by the developer's experience or trial and error. No experience or theoretical formula between them is available to people working in the field. This increases the time and efforts for designing and thus the production cost.

Therefore, it is highly desirable to provide a high-performance and low-noise fan and the method for selecting the motor size thereof that reduces the development time.

SUMMARY OF THE INVENTION

In view of the foregoing, the invention is to provide a high-performance and low-noise fan and the method for selecting the motor size thereof that reduces the development time.

To achieve the above, the invention discloses a fan including a frame, an impeller, and a motor. The impeller is accommodated in the frame. The motor drives the impeller and includes a rotor structure and a stator structure. The dimension Y of the frame and the diameter X of the stator structure meet an equation of Y=CX^(n), where C is a constant and n is a variable number.

To achieve the above, the invention also discloses a method for selecting the motor size of a fan. The method includes the steps of: providing a frame with a dimension Y of a frame and a stator structure with a diameter X; and obtaining the diameter X of the stator structure or the dimension Y of the frame according to an equation of Y=CX^(n). Wherein, C is a constant and n is a variable number.

As mentioned above, the invention requires that the frame dimension and the motor size meet the equation of Y=CX^(n). In comparison with the prior art, the invention can indeed find a suitable combination of the frame dimension and motor size. It achieves the goals of reducing the development time, maximizing the performance, and minimizing noise in the fans.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will become more fully understood from the detailed description given herein below illustration only, and thus is not limitative of the present invention, and wherein:

FIG. 1 is a schematic view of the conventional fan;

FIG. 2 is a schematic view of the fan according to a preferred embodiment of the invention;

FIG. 3 shows the relation between the dimension of the frame and the diameter of the stator structure in a fan according to the preferred embodiment; and

FIG. 4 is a flowchart of the disclosed method for selecting the motor size of a fan according to the preferred embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.

Please refer to FIG. 2. The fan 2 according to a preferred embodiment of the invention includes a frame 21, an impeller 22, and a motor 23. In the preferred embodiment, the fan 2 is an axial-flow fan.

The impeller 22 is accommodated in the frame 21. It has a hub 221 and several blades 222 disposed around the hub 221.

The motor 23 connects to the hub 221 and drives the hub 221 to rotate the blades 222. The motor 23 includes a rotor structure 231 and a stator structure 232. The rotor structure 231 includes a magnetically conductive shell 231 a, a magnetic element 231 b, and a shaft 231 c. The magnetic element 231 b is disposed on an inner surface of the magnetically conductive shell 231 a corresponding to the stator structure 232. The shaft 231 c is coupled to the magnetically conductive shell 231 a. The magnetically conductive shell 231 a connects to the hub 221 of the impeller 22. The stator structure 232 has an axial hole 232 a. The shaft 231 c of the rotor structure 231 is inserted through the axial hole 232 a and is pivotally disposed in the stator structure 232. The stator structure 232 drives the rotor structure 231 to rotate the impeller 22 so that the airflow is generated. As shown in FIG. 2, the X and Y are dimensions of the stator structure 232 and the frame 21, respectively.

As shown in FIG. 3, to increase the performance of the fan 2, i.e. the air pressure and flux, the dimension Y of the frame 21 and the diameter X of the stator structure 232 meet the equation of Y=CX^(n), where C is a constant and n is a variable number between 1 and 2.

In this embodiment, the equation is obtained through the following steps. First, the dimensions Y of several fans 21 and the diameters X of the stator structure 232 of several motors 23 are measured. The measured frame dimensions Y and stator structure diameters X are then examined using statistical analyses and recursion processes. The equation is obtained by taking the diameters X as the x-axis coordinates and the dimensions Y as the y-axis coordinates.

In particular, the fan 2 has a thickness greater than or equal to 1.5 inch or 38 mm. The dimension Y of the frame 21 is greater than or equal to 0.04 m and smaller than or equal to 0.12 m. A ration of the diameter X of the stator structure 232 to the dimension Y of the frame 21 is greater than or equal to 25% and smaller than or equal to 50%. That is, 25%≦X/Y≦50%. The variable number n is greater than 1 and smaller than 2. In this embodiment, the equation is Y=13.25X^(1.4)±5%.

A method for selecting the motor size of the fan 2 according to a preferred embodiment of the invention is illustrated in FIG. 4. The method includes steps S1 and S2. Step S1 provides a frame 21 with a dimension Y and a stator structure 232 with a diameter X. Step S2 obtains the diameter X of the stator structure 232 or the dimension Y of the frame 21 according to an equation of Y=CX^(n), where C is a constant and n is a variable number.

When applying the equation to the assembly of a fan 2, one first measures the dimension Y of the frame 21 or the diameter X of the stator structure 232. Using the equation, one obtains the diameter X of the stator structure 232 or the dimension Y of the frame 21 that satisfies the equation. This determines the dimension of the frame 21 and the size of the motor 23. Finally, the frame 21 with the dimension Y and the stator structure 232 with the diameter X are assembled to form the motor 23.

In summary, the invention requires that the frame dimension and the motor size meet the equation of Y=CX^(n). In comparison with the prior art, the invention can indeed find a suitable combination of the frame dimension and motor size. It achieves the goals of reducing the development time, maximizing the performance, and minimizing noise in the fans.

Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the invention. 

1. A fan comprising: a frame; an impeller accommodated in the frame; and a motor driving the impeller and comprising a rotor structure and a stator structure; wherein a dimension Y of the frame and a diameter X of the stator structure meet an equation of Y=CX^(n), where C is a constant and n is a variable number.
 2. The fan of claim 1, wherein Y is greater than or equal to 0.04 m and smaller than or equal to 0.12 m.
 3. The fan of claim 1, wherein the equation is Y=13.25X^(1.4)±5%.
 4. The fan of claim 1, wherein n is greater than 1 and smaller than
 2. 5. The fan of claim 1, wherein the fan has a thickness greater than or equal to 1.5 inches.
 6. The fan of claim 1, wherein the impeller includes a hub and a plurality of blades disposed around the hub.
 7. The fan of claim 1, wherein the fan is an axial-flow fan.
 8. The fan of claim 1, wherein a ratio of the diameter X of the stator structure to the dimension Y of the frame ranges between 25% and 50%.
 9. The fan of claim 1, wherein the rotor structure includes a magnetically conductive shell, a magnetic element, and a shaft, the magnetic element is disposed on an inner surface of the magnetically conductive shell corresponding to the stator structure, the shaft is coupled to the magnetically conductive shell, and the magnetically conductive shell connects to a hub of the impeller.
 10. The fan of claim 9, wherein the stator structure has an axial hole and the shaft of the rotor structure is inserted through the axial hole.
 11. A method for selecting the motor size of a fan, comprising the steps of: a providing a frame with a dimension Y and a stator structure with a diameter X; and obtaining the diameter X of the stator structure or the dimension Y of the frame according to an equation of Y=CX^(n); wherein C is a constant and n is a variable number.
 12. The method of claim 11, wherein Y is greater than or equal to 0.04 m and smaller than or equal to 0.12 m.
 13. The method of claim 11, wherein the equation is Y=13.25X^(1.4)±5%.
 14. The method of claim 11, wherein n is greater than 1 and smaller than
 2. 15. The method of claim 11, wherein the fan has a thickness greater than or equal to 1.5 inches.
 16. The method of claim 11, wherein a ratio of the diameter X of the stator structure to the dimension Y of the frame ranges between 25% and 50%.
 17. The method of claim 11, wherein the rotor structure includes a magnetically conductive shell, a magnetic element, and a shaft, the magnetic element is disposed on an inner surface of the magnetically conductive shell corresponding to the stator structure, the shaft is coupled to the magnetically conductive shell, and the magnetically conductive shell connects to a hub of the impeller.
 18. The method of claim 17, wherein the stator structure has an axial hole and the shaft of the rotor structure is inserted through the axial hole.
 19. The method of claim 11, wherein the fan is an axial-flow fan. 